Who started creationism?
The first known usage of the word Creationism was by Darwin (in 1856), who used the term "Creationists" to describe contemporary proponents of Creation such as Philip Gosse. Gosse and other 19th-century religious scientists were responding to the atheistic or naturalistic ideas of the time; but actually in a fundamental sense, Creationism may be said to be as old as Adam, since the ancients all believed that the universe had a supernatural source. See also:
God started it on day one of creation. Mankind has believed it from
the beginning of creation, since man was there and a part of it.
Adam and Eve know the story to be true. A more appropriate question
would be "Who started the idea of evolution?" because that is a
fairly new belief. You will not find any writings as old as the
Bible that teach evolution.
Most anthropologists agree that religiosity (and creationist
stories) began sometime around 50,000-200,000 years ago, although
it might have been quite a bit earlier but that is when the first
good evidence for religion appears. Every culture since has
attempted to explain their existence by invoking a different
version of creationism.
If you are referring to the modern young earth creation movement,
then the book, The Genesis Flood, by the late Dr Henry Morris and
Dr John Whitcomb in 1961 was an important starting point. Dr Morris
has been called the father of the modern creation movement.
Creationism has existed in some form for around 6000 years, as per
the records of Jewish and then Christian society. In its modern
form, creationism sprung up around the same time as evolution, as a
response to defend against what was seen as a threat to their
The people who developed both are either not known in the first
case, or many and varied in the second.
Strictly speaking, 'creationism' is a doctrine that was developed in response to Darwin's Theory of Evolution by Natural Selection and other scientific advances. There have been so many strands of creationism, notably 'Old-Earth' creationism and 'Young-Earth' creationism, that it is unclear who really started the movement, but this was probably in the second half of the nineteenth century, after Charles Darwin published On the Origin of Species. It has been said that what really sparked the modern creationist movement was the publication in 1961 of the book titled The Genesis Flood, written by Henry Morris and John Whitcomb.
For more information, please visit: http://christianity.answers.com/theology/the-story-of-creation